Regulation ofAnguillicola crassus(Nematoda) infrapopulations in their definitive host, the European eel,Anguilla anguilla

Parasitology ◽  
2008 ◽  
Vol 135 (14) ◽  
pp. 1707-1716 ◽  
Author(s):  
G. FAZIO ◽  
P. SASAL ◽  
C. DA SILVA ◽  
B. FUMET ◽  
J. BOISSIER ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Anguilla Anguilla ◽  
The Body ◽  
European Eel ◽  
Swim Bladder ◽  
Experimental Conditions ◽  
Larval Stages ◽  
Resource Limited ◽  
Third Stage ◽  
Opposite Sex

SUMMARYThe parasitic nematodeAnguillicola crassuswas recently introduced into populations of the European eel,Anguilla anguilla. We investigated, under experimental conditions, the regulation ofA. crassusinfrapopulations. We tested the effects of (1) the resource-limited habitat of the parasite and (2) the coexistence of several developmental stages in its niche (the swim-bladder) on the composition of the infrapopulations. The results revealed that the respective effects of these factors differed substantially during the course of the infection. Third-stage larvae (L3s) establishment would not be constrained by the size of the swim-bladder. Their moult to fourth-stage larvae (L4s) would be accelerated as the number of L3s increased. The moulting time of L4s to adults would be reduced by males and would be constrained by the size of the swim-bladder. However, the moult of L4s to adults and their further development would be synchronized with those of the opposite sex. At the time of mating, the number of males and the body weight of adults would depend on the size of the swim-bladder. Soon after the laying of eggs, the developmental constraint on the late L3s would decrease. When adults die, constraints would cease and late larval stages would moult to become adults.

scholarly journals Seasonal occurrence of some larval stages of endoparasites in three cyprinids from the Nwanedi-Luphephe dams, the Limpopo River System, South Africa

2015 ◽  
Vol 52 (3) ◽  
pp. 229-235 ◽  
Author(s):  
E. M. Mbokane ◽  
J. Theron ◽  
W. J. Luus-Powell
Keyword(s):  
Developmental Stages ◽  
River System ◽  
Intestinal Wall ◽  
The Body ◽  
Seasonal Occurrence ◽  
Seasonal Fluctuations ◽  
Metazoan Parasites ◽  
Larval Stages ◽  
Parasite Communities ◽  
Third Stage

Abstract This study provides information on seasonal occurrence of developmental stages of endoparasites infecting three cyprinids in the Nwanedi-Luphephe dams, Limpopo River System. Labeobarbus marequensis (Smith, 1841), Barbus trimaculatus Peters, 1852 and Barbus radiatus Peters, 1853 were investigated seasonally from January 2008 to October 2008. The following larvae of metazoan parasites were collected: Diplostomum sp. from the eyes of L. marequensis and B. trimaculatus; Ornithodiplostomum sp. from the gills of B. trimaculatus; Posthodiplostomum sp. from muscle, skin and fins of B. trimaculatus and B. radiatus; third-stage Contracaecum larvae (L3) from the mesentery fats and on the liver lobes of L. marequensis and B. trimaculatus and gryporynchid cestode larvae from the outer intestinal wall of B. radiatus. All the flukes encountered were metacercariae. Diplostomum sp. and Contracaecum sp. dominated the parasite communities. Their prevalence exhibited seasonal fluctuations with maxima in summer. Factors likely to influence fish infection such as the body size of fish and their condition factors were also briefly considered in this study.

scholarly journals Relationships of Otolith Dimension with Body Length of European Eel Anguilla anguilla (Linnaeus, 1758) from Adriatic catchment of Montenegro

2018 ◽  
Vol 59 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Tamara Kanjuh ◽  
Danilo Mrdak
Keyword(s):  
Linear Function ◽  
Body Length ◽  
Somatic Growth ◽  
Anguilla Anguilla ◽  
Body Growth ◽  
The Body ◽  
European Eel ◽  
Fish Size ◽  
Sagittal Otolith ◽  
The Relationship

This study examined the relationship between the sagittal otolith morphometric variables (length, height and weight) and body growth of the European eel. Eels that were studied ranged in total length from 11.2 to 79.5 cm. The relationships between the sagittal otolith variables and fish somatic growth were described with a non-linear function. The resulting coefficients of determination \((r^2)\) ranged from 0.782 to 0.914. The variable most strongly related to fish size was found to be the sagittal otolith length (OL) with 91.4 % of the variability. The results of this study provide the first comprehensive data regarding the relationship between the sagittal otolith morphometric variables with the body length of Anguilla anguilla.

The life cycle of Paraquimperia tenerrima: a parasite of the European eel Anguilla anguilla

2005 ◽  
Vol 79 (2) ◽  
pp. 169-176 ◽  
Author(s):  
J.A. Shears ◽  
C.R. Kennedy
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Temperature Dependent ◽  
Free Living ◽  
Freshwater Invertebrate ◽  
Third Stage ◽  
History Of ◽  
Whole Life Cycle

AbstractPrevious studies on the life history of the nematode eel specialist Paraquimperia tenerrima (Nematoda: Quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. In the laboratory, eggs failed to hatch below 10°C, hatching occurring only at temperatures between 11 and 30°C. Survival of the free-living second stage larvae (L2) was also temperature dependent, with maximal survival between 10 and 20°C. Total survival of the free-living stages (eggs and L2) is unlikely to exceed a month at normal summer water temperatures, confirming that parasite could not survive the 6 month gap between shedding of eggs in spring and infection of eels in early winter outside of a host. Eels could not be infected directly with L2, nor could a range of common freshwater invertebrate species. Third stage larvae (L3) resembling P. tenerrima were found frequently and abundantly in the swimbladder of minnows Phoxinus phoxinus from several localities throughout the year and were able to survive in this host in the laboratory for at least 6 months. Third stage larvae identical to these larvae were recovered from minnows experimentally fed L2 of P. tenerrima, and eels infected experimentally with naturally and experimentally infected minnows were found to harbour fourth stage larvae (L4) and juvenile P. tenerrima in their intestines. Finally, the whole life cycle from eggs to adult was completed in the laboratory, confirming that minnows are an obligate intermediate host for P. tenerrima.

The swimbladder nematodeAnguillicola crassusin the European eelAnguilla anguillaand the Japanese eelAnguilla japonica: differences in susceptibility and immunity between a recently colonized host and the original host

2006 ◽  
Vol 80 (2) ◽  
pp. 129-136 ◽  
Author(s):  
K. Knopf
Keyword(s):  
Anguilla Anguilla ◽  
Preliminary Evidence ◽  
Japanese Eel ◽  
Indigenous Populations ◽  
Acquired Immunity ◽  
European Eel ◽  
New Host ◽  
Protective Function ◽  
Original Host ◽  
Third Stage

AbstractThe swimbladder nematodeAnguillicola crassusoriginates from Asia where it is a parasite of the Japanese eelAnguilla japonica. After its introduction to Europe about 25 years ago, the parasite spread rapidly within the indigenous populations of the European eelAnguilla anguillaand subsequently the prevalence and mean intensity appeared to stabilize. Under experimental and aquaculture conditions the naïve new host appears to be more susceptible toA. crassuscompared to the original host. Both eel species develop a immune response againstA. crassus. The antibody response is well characterized for the European eel, but poorly characterized for the Japanese eel. It remains unclear if antibodies have any protective function againstA. crassus. Encapsulation of larvae ofA. crassuscan be observed in naturally infected European eels. However, encapsulation of larvae following experimental infection has not been detected in European eels, but only in Japanese eels. Reinfection experiments and intraperitoneal injection ofA. crassushomogenates failed to demonstrate the development of acquired immunity in European eels. Immunization with irradiated third stage larvae provided preliminary evidence for acquired immunity againstA. crassusin the Japanese eel, but not in the European eel.

scholarly journals Estimation of the Coefficients of the Equation of Acoustic Target Strength Based on the Morphology of Coregonus migratorius (Georgi, 1775) Swim Bladder

2020 ◽  
Vol 15 (1) ◽  
pp. 89-98
Author(s):  
P. N. Anoshko ◽  
M. M. Makarov ◽  
S. B. Popov ◽  
A. I. Degtev ◽  
N. N. Denikina ◽  
...  
Keyword(s):  
Acoustic Scattering ◽  
Morphological Characteristics ◽  
Prolate Spheroid ◽  
The Body ◽  
Target Strength ◽  
Fish Length ◽  
Swim Bladder ◽  
Experimental Conditions ◽  
Scattering Model ◽  
Acoustic Target

Aim. The aim of the study was to estimate the coefficients of the equation TSmax=f(SL) considering the characteristics of an acoustic scattering model based on the morphological characteristics of the swim bladder of the Coregonus migratorius (Georgi, 1775). Material and Methods. Ninety‐nine living specimens of C. migratorius served as the study material. For each specimen, the target strength in the cage was measured using an Kongsberg Simrad EY500 echo sounder and the morphology of the swim bladder was studied. Measurements, analysis of images and data were conducted using Image Pro 6.0. Excel and SciLab software resources. Results. We determined the main morphological characteristics of the swim bladder in C. migratorius as well as the correspondence of its dimensions and proportions in relation to the length of the fish’s body. The coefficients of the equation TS=20log(SL)‐60, calculated on the results of the acoustic scattering model of a prolate spheroid, agree well with the coefficients calculated from maximum values obtained in the cage experiment. During the conversion of the coefficients relating to the allometric changes in the length of the swim bladder relative to fish length, the equation TS=23.2log(SL)‐64.4 was obtained. A comparative analysis of the available equations of the target strength for C. migratorius with those obtained in the study was undertaken. Conclusion. The equation obtained on the model of the swim bladder as a prolate spheroid adequately describes the dependence of the maximum values of the target strength on the body length of the C. migratorius and confirms the previously obtained dependence by maximum values of TS in the cage experimental conditions and can serve as a basis for further theoretical studies.

scholarly journals Myonuclear content regulates cell size with similar scaling properties in mice and humans

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenth-Arne Hansson ◽  
Einar Eftestøl ◽  
Jo C. Bruusgaard ◽  
Inga Juvkam ◽  
Alyssa W. Cramer ◽  
...  
Keyword(s):  
Cell Size ◽  
Developmental Stages ◽  
Scaling Law ◽  
Muscle Fibers ◽  
The Body ◽  
Experimental Conditions ◽  
Scaling Properties ◽  
Nuclear Number ◽  
The Relationship ◽  
Developing Mice

AbstractMuscle fibers are the largest cells in the body, and one of its few syncytia. Individual cell sizes are variable and adaptable, but what governs cell size has been unclear. We find that muscle fibers are DNA scarce compared to other cells, and that the nuclear number (N) adheres to the relationship N = aVb where V is the cytoplasmic volume. N invariably scales sublinearly to V (b < 1), making larger cells even more DNA scarce. N scales linearly to cell surface in adult humans, in adult and developing mice, and in mice with genetically reduced N, but in the latter the relationship eventually fails when they reach adulthood with extremely large myonuclear domains. Another exception is denervation-atrophy where nuclei are not eliminated. In conclusion, scaling exponents are remarkably similar across species, developmental stages and experimental conditions, suggesting an underlying scaling law where DNA-content functions as a limiter of muscle cell size.

LABORATORY STUDIES ON THE TOXICITY OF INSECTICIDES TO THE BERTHA ARMYWORM (MAMESTRA CONFIGURATA) (LEPIDOPTERA: NOCTUIDAE)

1975 ◽  
Vol 107 (8) ◽  
pp. 865-872 ◽  
Author(s):  
C. R. Harris ◽  
S.A. Turnbull
Keyword(s):  
Direct Contact ◽  
Developmental Stages ◽  
Contact Toxicity ◽  
Mamestra Configurata ◽  
Larval Stages ◽  
Large Numbers ◽  
Third Stage ◽  
History Of ◽  
Dual Objectives ◽  
Bertha Armyworm

AbstractThis study had dual objectives: to select a series of insecticides toxic to the bertha armyworm, Mamestra configurata (Walk.), and to determine susceptibility of the various developmental stages to insecticides. Pupae were collected from infested rapeseed fields in Alberta and a laboratory rearing procedure suitable for production of large numbers of insects was devised. The direct contact toxicity of 50 insecticides to third-stage larvae was assessed. Methomyl and DDT were included as standard insecticides. None of the experimental insecticides was as toxic as methomyl but about one half were more toxic than DDT. Tests with representative organochlorine, organophosphorus, and carbamate insecticides indicated that all caused rapid knockdown of third-stage larvae. There was no evidence of subsequent recovery. After the life history of the bertha armyworm under controlled environmental conditions was determined, tests were conducted to ascertain the susceptibility of the various developmental stages to methomyl, chlorpyrifos, leptophos, and methidathion. Eggs and first and second stage larvae were more susceptible to direct contact applications of the insecticides than were the later larval stages, pupae, and adults.

Biology, morphology and anatomy of aphidophagous syrphid larvae

Parasitology ◽  
1939 ◽  
Vol 31 (1) ◽  
pp. 78-120 ◽  
Author(s):  
Madan Lal Bhatia
Keyword(s):  
Comparative Morphology ◽  
The Body ◽  
Individual Species ◽  
Larval Stages ◽  
The Third ◽  
Third Stage ◽  
Mode Of Life ◽  
Pass Through ◽  
The Individual ◽  
Syrphid Larvae

The paper deals with the biology, morphology and anatomy of seven species of syrphid larvae viz. Syrphus luniger Meig., S. balteatus De Greer, S. ribesii Linne, Catabomba pyrastri Linne, Sphaerophoria flavicauda Zett., Sph. scripta Linne, and Platychirus scutatus Meig.The habitat, mode of progression, aphidophagous habits and characteristic coloration are described for each species.It is shown that the larvae of all the above species, like larvae of other cyclorrhaphous Diptera, definitely pass through three stages separated by two moults. The mode of dehiscence of the puparium is described briefly.Each of the species, except Catabomba pyrastri, has three generations in the breeding season which lasts from May to October. Platychirus scutatus hibernates only in the larval stage, but the other species may be found in both the larval and pupal stages during the winter.The larvae of all the above species, except Syrphus balteatus, are commonly parasitized by ichneumonid larvae.The morphology of the egg, the three larval stages and the puparium of S. luniger is described in detail.The characters common to the third stage larvae of all the species dealt with are summarized and short descriptions of the third stage larvae and puparia of the individual species are given. The general appearance of the living larvae and details of the buccopharyngeal armature, spiracles and puparia of each of the species is represented in figures.In connexion with the pupae a number of new structures are described and it is suggested that some of them are concerned with the formation of the characteristic shape of the puparium and with the dehiscence of the puparium.Internal pupal spiracles are present in all the species dealt with, but external pupal spiracles are present only in Platychirus scutatus.The anatomy of P. scutatus is described and figured, an account being given of all the structures except the musculature of the body wall. Study of the anatomy affords evidence as to the carnivorous mode of life of the larvae and also indicates that the larvae have evolved from aquatic forms.The comparative morphology of the Syrphinae is discussed with respect to the relationship of the Syrphinae to other Aschiza and to the cyclorrhaphous Diptera.

Morphometric and morphological characteristics for identifying the life stages of Xiphinema bakeri Williams, 1961 (Nematoda: Longidorinae)

1970 ◽  
Vol 48 (4) ◽  
pp. 771-773 ◽  
Author(s):  
Jack R. Sutherland ◽  
T. G. Dunn ◽  
N. Bruce F. Cousens
Keyword(s):  
Morphological Characteristics ◽  
The Body ◽  
Life Stages ◽  
Larval Stages ◽  
Second Stage ◽  
The Third ◽  
Clear Area ◽  
Third Stage ◽  
Tail Shape ◽  
Tail Tip

Several morphometric and morphological characteristics were evaluated to determine their usefulness in identifying the life stages of Xiphinema bakeri. The stages can be identified by length of the body, onchiostylet, and replacement stylet of larvae. These values increase lineally from first-stage larva to adult, and fall into five groups corresponding to the nematodes' four larval stages and adult. Each stage has a specific tail-tip shape, which gradually changes from subacute in the first and second stages to subdigitate in adults. At lower magnifications, the body length and the tail shape, used in combination, are best for identification. First-stage larvae also have the replacement stylet overlapping the stylet extension, distinguishing them from the second stage. Frequently the immature vagina of fourth-stage larvae appears as a clear area in the body; this helps to separate them from the third stage.

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